Cancer, also known as malignant neoplasm, is characterized by an abnormal growth of cells that display uncontrolled cell division, invasion and destruction of adjacent tissues, and sometimes metastasis to other locations in the body. There are more than 100 types of cancer, including breast cancer, skin cancer, lung cancer, colon cancer, prostate cancer, and lymphoma. Cancer is the second leading cause of death in America and it causes about 13% of all deaths. Cancer may affect people at all ages, even fetuses, but the risk for most types of cancer increases with age. Cancers can affect all animals.
Stereotactic body radiation therapy (SBRT) utilizes a three-dimensional coordinate system to achieve accurate radiation delivery. With SBRT, the radiation planning margins accounting for set-up uncertainty are minimized. This allows for greater dose-volume sparing of the surrounding normal tissues, which enables the delivery of higher and fewer fractional doses of radiation (hypofractionation). With SBRT, discrete tumors are treated with the primary goal of maximizing local control (akin to surgical resection) and minimizing toxicity. SBRT may be defined as a radiation planning and delivery technique in which a three-dimensional orientation system is used to improve targeting accuracy, typically as a hypofractionated (1-5 fractions) regimen.
Despite these new agents and improved combinations, the current treatment is still not effective for many types of cancers or cancers at different stages. Improved regimens and treatments are greatly needed for cancer therapy.